We wish to document our activity in processing fresh samples of carcinoma of the prostate in culture and as heterografts in nude mice. We have consistently obtained a primary outgrowth from fragments seeded in tissue culture. But we have not been able to subculture such outgrowths after trypsinizing them, so as to be able to count cells or measure cell growth with our rubidium technique (as planned in the protocol). We have obtained growth into a tumor mass of four inoculations of carcinoma into nude mice. The tumors showed glandular structures more reminiscent of benign prostatic hypertrophy than of the original cancer. We are now attempting to do karyotypes on the "rescued" tumors and to passage them further to define their nature. It is of interest that such growth was obtained only in testosterone treated nude mice. We have become very interested in pursuing the finding that the prostate is an immunologically privileged site and its significance. We will be incorporating studies in this grant's activity to implant tumors into the substance of the prostate. The immunological reactivity of the prostate to classic antigens will be tested in guinea pigs and inbred rats.